Conventionally, when a user has input or output document data using an input/output device such as a scanner or printer, the user is charged for use of the device.
In this conventional charge scheme, the number of pages of input/output document data is counted in units of input/output devices used for input/output, and the user is uniformly charged using the count information.
Generally, a variety of software for document editing or document input/output are available at different costs.
For example, when a document is output, its style changes depending on the software used. In addition, some software cannot process full-color data but can process only, e.g., 256 (pseudo) colors.
In the prior art, however, the user is charged using only the count information of each input/output device. For this reason, when the numbers of input/output pages equal, the charges also equal independently of the type and quality of the software used.